The human body is made up of millions of cells that vary in shape, size and function. In healthy tissues, new cells are created during cell division, a process called mitosis. When cells become old, they "self-destruct" and die, a process called apoptosis. A delicate balance must exist between the rate at which new cells are created and the rate at which old cells die. Cancer develops when the balance is disrupted and cells grow out of control. Chemotherapy is a type of treatment that uses strong medicines to stop the growth of cancer cells. Chemotherapy can be administered in several ways: - It can be administered as a pill, - given as an injection, - or, given intravenously through a central line. Once the drugs enter the body, they destroy cancer cells by preventing them from growing or multiplying during mitosis. Depending on the stage of a patient's cancer, chemotherapy can be used to cure cancer, stop cancer from spreading, or relieve cancer symptoms. It can be used alone, or in combination with other therapies, such as with surgery or radiation. Unfortunately, chemotherapy also harms healthy cells, especially cells that divide quickly. These include cells in the hair, blood, bone marrow, and reproductive organs. Harm to healthy cells is what causes side effects. Some side effects may include hair loss, nausea and vomiting, fatigue, suppression of the immune system, and anemia.